VATICAN CITY — Pope Francis encouraged the faithful on Friday to guard their hearts by doing a daily examination of conscience, saying that, we if we don’t, we risk letting the devil in rather than the Lord.

“Guard the heart, as a house is guarded, with a key. And then watch the heart, like a sentinel: How often do wicked thoughts, wicked intentions, jealousy, envy enter in?” the Pope asked his Oct. 10 Mass attendees.

The devil, he cautioned, “never leaves that which he wants for himself,” which are our souls, meaning that he keeps trying to tempt us.

Pope Francis began his reflections by turning to the day’s Gospel reading from Luke Chapter 11, in which Jesus is accused of casting out demons by the power of demons and in which he describes how when an evil spirit leaves a person it comes back with more and makes the person worse off than before.

Satan never leaves us alone, he said, explaining that after Jesus was tempted in the desert, “the devil left him for a time, but during the life of Jesus, he returned again and again: when they put him to the test, when they tried to trap him, in the Passion [and] finally on the cross.”

“Can you do it? Let me see!” are phrases that hit home for all of us, the Holy Father noted, observing how the devil not only tempts Jesus in this way, but also each of us.

We need to guard our hearts, he said, otherwise, “so many things enter in. But who has opened that door? Where do they enter from?”

“If I do not realize [how much] enters into my heart, my heart becomes a [place] where everything comes and goes.” It becomes “a heart without intimacy, a heart where the Lord cannot speak and cannot even be heard,” the Pope explained.

He then drew attention to how in the Gospel Jesus says, “He who does not gather with me scatters,” saying that the meaning of “gather” in this sense means: “to have a gathering heart, a heart in which we know what happens.”

A practice “as old as the Church” that we can perform in order to help us achieve this type of heart, he noted, is the examination of conscience.

“Who of us, at night, at the end of the day, remains by himself, by herself and asks the question: What happened today in my heart? What happened? What things have passed through my heart?” the Pope probed, saying that if we don’t do this we fail to guard our hearts well.

To guard our heart is “a grace,” the Pope explained, because by doing so, we guard not only ourselves, but also the Holy Spirit, who dwells inside of us.

“We know — Jesus says clearly — that the devil always returns. Even at the end of life, he, Jesus, gives us an example of this,” the Holy Father pointed out.

Pope Francis concluded his homily by encouraging all to “stand in silence before ourselves and before God, and at the end of the day ask ourselves: ‘What happened today in my heart? Did anyone I don’t know enter? Is the key in its place?’”

By doing this, we will defend ourselves from the wickedness of the devil, and “from that which we could do if these demons, who are very clever and at the end would cheat all of us, enter.”